CH₃NH₃PbI₃ And CsPbX₃ Perovskite Solar Cells

The rapid development of organic-inorganic hybrid and all-inorganic pervoskite materials have drawn widely attention in energy field.Within a decade,the PCE of perovskite solar cells has exceeded 23.7%from 3.8%.With such a promising commercialization potential,the perovskite solar cells still have many problems to be solved,such as poor ambient stability,heavy metal toxicity and expensive additives.Herein,we originated a low cost way-static magnetic field application-to improve the crystallinity of CH3NH3PbI3thin films and its device performance,fabricated high performance CsPbIBr2 solar cells,studied the phase segregation mechanism of CsPbIBr2 thin films and explored the possibility of improving the stability of CsPbI3 materials and solar cells by introducing PEAI organic molecule.The study results are shown below.In the first work,we first proposed that using static magnetic field to improve the crystallinity of CH3NH3PbI3thin films.Through 80 mT static magnetic field application during spin-coating,we enlarged the average grain size of CH3NH3Pbl3thin film to 192nm from 148nm boosted the PCE up to 18.56%from 16.72%.The device performance was enhanced by 1.84%and the stability was also improved.In the second work,we explored the CsPbIBr2 thin films and solar cells fabrication via dual-source thermal evaporation.A best device performance up to7.4%which is highest at that time was gained through adjustment of molar ratio,substrate temperature,annealing temperature and annealing time.The device performance decay in ambient with 25%-35%relative humidity is less than 10%for 30 days.Furthennore,we demonstrated the principle of the intrinsic phenomenon of phase segregation in CsPbIBr2 thin films via EDX characterization.The phase segregation is intrinsic characteristics of CsPbIBr2 thin films which can not be eliminated completely.In the third work,we studied the fabrication of 3D CsPbI3 and low dimensional RP structure CsPbI3 thin films and solar cells through spin-coating.The device performance of 3D CsPbI3 solar cells is 14.84%.The stability of CsPbI3 thin films was improved by introducing the PEAI organic molecule.The stability of phase transformation of low dimensional RP structure CsPbI3 thin films was prolonged to 7 days in ambient with 85%-90%relative humidity.In addition,we demonstrated the micromechanism of phase transformation of CsPbI3 thin films which proved that the existence of PEAI organic molecule can stable the CsPbl3thin films through its hydrophobicity.